[docs] Apparent bug in python socket howto

Thanks for the howto.  It's a great conceptual introduction, and I was happy to have it to read when I needed to get my hands a bit dirtier than using SocketServer. But the statement  "If we had used s.bind(('', 80)) [the socket would only be] visible within the same machine." appears to be incorrect. As the socket module documentation states, "the empty string represents INADDR_ANY." Thanks and best regards, Patrick Maupin Austin, Texas